The advantage of S/MIME (Secure/Multipurpose Internet Mail Extensions) in comparison with PGP is mainly that S/MIME-Certificates are usually handed out by well-known Certification Authorities (CAs) which also sell SSL/TLS-Certificates. This encourages reliance severely.
In contrast, PGP (Pretty Good Privacy) relies on private keys. Those are generated while the e-mail-address is installed and therefore have to be exchanged by the conversational partners. As a result, users have to decide themselves which conversational partner they believe is trustworthy.
The fact that this isn’t easy can be explained further by our support-team. The number to call is: +49 661 480 276 10.